I'm trying to move to OPNSense - will this topology function correctly?

[tdalej]

Does this not make any sense, or did I post to the wrong forum?
100+ views and zero responses.



I have a somewhat odd network topology due in part to new ISP provider availability and the addition of some 10GB capable network equipment.
This started with ISP1 and LAN1. 
I added the interface for the Wireless network and isolated wireless from the wired network.
Later, a new building was added and because of location an alternate ISP was available.
(One ISP is DSL, the other line of sight radio link, so no point in trying to do HA on the two links - the speed and latency are so different and the utilization between the two buildings suit the WAN link in use.)

I have services in both buildings, but make the local firewall the first DNS and the remote firewall second DNS in each environment.
This worked well with LAN3 being nothing but the link between the buildings.
I lucked into some 10G equipment and upgraded the interfaces on the firewall and switches on both ends of the 10G link so that I have enough ports on both ends for workstations on one end and NAS (like) servers on the other.

This works -- there are some odd quirks with routing, but I know where not to step to avoid them after a bit of trial and error.

I'm trying to replicate this frankenmonster into OPNSense.

Is this possible?
Is there a better way?  (Preferably without a steep learning curve.)
Hopefully the crude image I drew helps the explanation -- and it shows up.